Heavy odor of stool may be caused by improper diet, intestinal flora imbalance, colon cancer and other factors. 1. Improper diet: when protein enters the intestine, it may decompose and produce ammonia, hydrogen sulfide and other substances, which may have a certain odor. If the proportion of food with high protein content in daily diet is significant, it may lead to the concentration of protein decomposition products in the feces to increase, thus leading to the heavy odor of feces. 2. Intestinal flora imbalance: The flora in the intestines can be divided into three categories, namely, beneficial bacteria, harmful bacteria and symbiotic bacteria. When the number of harmful bacteria increases, they may decompose the intestinal contents and produce some smelly substances, and if these substances are discharged with the stool, heavy stool odor may occur. 3. Colon cancer: colon cancer is a kind of malignant tumor occurring in colon, with the growth of tumor, on the one hand, it may make the intestinal lumen narrow, resulting in the intestinal contents staying in the intestinal tract for a long time; on the other hand, the tumor tissues may be necrotic, and the necrotic tissues may produce smelly substances. On the other hand, the tumor tissue may be necrotic, and the necrotic tissue may produce foul-smelling substances. Therefore, heavy odor of stool may also be caused by colon cancer. When the situation of heavy odor in stool occurs, you should consult doctor in time, and improve the routine stool, stool culture, colonoscopy and other examinations under doctor’s guidance to clarify the cause of the disease, and follow the doctor’s instruction for treatment.